1. Field
One or more embodiments relate to an anti-seismic apparatus for control element drive mechanisms, and more particularly, to an anti-seismic apparatus for supporting a plurality of control element drive mechanisms using an integral anti-seismic support plate to prevent excessive transverse movements of the control element drive mechanisms.
2. Description of the Related Art
Control element drive mechanisms are used to control the reactivity of nuclear fuel in a reactor core. Control element drive mechanisms vertically lift or lower control elements (control rods) for taking the control elements out of the reactor core or inserting the control elements into the reactor core.
FIG. 1 illustrates reactor upper structures of the related art, and FIG. 2 illustrates main parts of FIG. 1.
Referring to FIG. 1, various structures are disposed on an upper side of a reactor head, and such structures are called reactor upper structures. Examples of the reactor upper structures include a cooling fan for cooling control element drive mechanisms, a shroud shell for accommodating the reactor upper structures and providing cooling-air flow passages, a lifting device for lifting the reactor upper structures, a cable device for supplying power to the control element drive mechanisms, and an anti-seismic apparatus for the anti-seismic design of the control element drive mechanisms.
Referring to FIG. 2, a plurality of control element drive mechanisms are illustrated. In the related art, anti-seismic apparatuses for control element drive mechanisms are constructed by individually installing anti-seismic support plates on the control element drive mechanisms to transmit a load through contact between neighboring anti-seismic support plates and restrict transverse movements of the control element drive mechanisms.
However, such anti-seismic support plates disposed at respective control element drive mechanisms may make manufacturing and installing processes inconvenient.
In addition, if anti-seismic support plates are individually installed on respective control element drive mechanisms as in the related art, due to thermal expansion of the anti-seismic support plates, the control element drive mechanisms may be inclined, or neighboring anti-seismic support plates may not be horizontally aligned with each other. Furthermore, since gaps between the anti-seismic support plates are not always constant, impactive forces may not be stably transmitted during earthquakes.